Transformer.



M. EASTHAM. ,Y TRANSPOBMBB. 'APPLICATION FILED SEPT. 3, 1909.

. ,965,168 Patented Ju1y26,191o.

Zaweg.- Im/erwan' gmgw @Mgg UNITED STATES PATENT oEEicE.

MELVILLE EATHAM, OF BOSTON, MASSACHUSETTS, SSIGNGR T0 .CLAPP-EASTHAM COMPANY., `QE'.IIOSLONQ .MASSAGHUSETTS, A...CQBPQRATIQN. DF'MASSACHUSETTS.

Specification ot .Letters Patent.

ratented'auiya, 1910.

,sepia-mamma september 3.11909. seriaiiuossiaoa?.

To all whom 'it'may concern: f p

IBe it-.lmown thatI, MELvILLn'EAsr, ",M, a citizen ofthe United States, and residentwof Boston,-in'the county of `Su'ifolk and'State of Massachusetts, have invented new. and

'useful Improvements in Transformers, of

` which the following isa 'speci-fication.l

My invention relates to apparatus for charging condensers and is peculiarly applicable to circuits employed in wireless telegraphy, wherein -a transformer is used to charge a condenser. l i

The objects of my invention are; to pre* vent the formation of an arc at the spark .gap in' such circuits, to cause a decrease of current in the primary of the transformer when the secondary `is short circuited by the operation of the spark gap, to dispense with control resistance or inductance and to enable the primary of the transformerto be tapped at any number of different points so as to vary the power of the instrument, to reduce both primary and secondary resistance -to lower quantities than are com'- inon in most types of transformers, and to secure a high power factor by oifsetting the leading current due to the condenser caiil pacity by the lagging current due to the inductance of the transformer secondary.

In the drawings hereto annexed which show in diagrammatic form ans example of my invention, A land D are the primary and secondary respectively of a closed core, trans.- former, the core of which is represented byl B. The primary A may be tapped from various .points in its winding. The magnetic leakage of the closed core transformer' is large; this large leakage is secured by the intermediate core spur C which is joined tov or preferably integral with the core B at 1 one side land `is separated from the other side of .the core by a very thin` air gap at E.

The resonant circuit of which the secondary D is a component part lcontains the `condenser H in series .with'the secondary coil and the spark gap .F in shunt across the condenser. This `spark gap vfor purposes hereinafter to be set forth is preferably adjustable. The secondary D is constructed so that its inductive reactance closely approximates to the capacity reactance of the condenser H for whatever alternating current this approximation. of reactance allows-a large current to ow into the condenser ofi the secondary is decreased whenever the 'the energy needed to charge when charging for the reason that the inductance is neutralized -by the capacty Aofthecondenser. When however, the condenser is .dischargedI at the spark gap "E, the previously existingresonant condition of the circuitis destroyed-by the formation of -spark,1an`d the full inductance of the n a seco ry being thus brought into play, the

. current is lowered to such an extent that it will not maintain an arc at the spark gap F.

When the secondary is open circuited the' lines of force from .the rimary A follow the closed magnetic circuit B but whenthe secondary is short circuited by the operation of the spark gap F, the opposing magnetic field caused by the current in the secondary obliges most of the lines of force from the primary A to complete themselves through' l the magnetic-leakage tongue C, crossing the air gap E.

By means of the above described arranger ment the formation of an arc at the spark gap is prevented, the current in the primary l secondary is short c1rcu1ted,the transformerA doesnot require the use of a controlling resistance or inductance as the primaryv may be tapped at any one of several points thus allowing the op! erator to choose between several available amounts of power. `Moreover. the resistance of the primary and secondary may be made much lower than usual by reason of the current' vcontrol by reaction between the several members of the transformer. If desired, a spark frequency lower than that of the supply current may be obtained by opening the adjustable spark gap F so far that several successive cycles are required to accumulate the condenser H to the sparking potentia It will be obvious also that the power factor of the transformer is high because the leading current due to the capacity of the condenser is neutralized by the lagging current caused by the inductance of the transformer secondary, since the capacity reactance of the one is equal or approximately so to the inductive reactance of the other.

What I claim and desire vto secure by Letters Patent 'is:-

l. A resonant circuit comprising the sec- .ondary of a closed corel transformer characterized by large magnetic leakage, a condenser in circuit with the .said secondary, the secondary having an inductive reactance ibo approximately equal to the capacity reactance of the condenser for the alternationfrequency of the supply current.

2. "A resonant', circuit oomprisingthe secondary vof a closed-core transformer which has aj nearlyl closed magnetic shunt, a conl denser in circuit with said secondary, the

secondary* having an inductive reactance approximately equal t0`the capacity reactance of the vcondenser for the a1ternation-frequencyof'the supply current.l v

3L The combination of a closed core transformer having .large ma etic leakage, a condenser in-series with t e secondary having an. inductive reactance approximately equal tothe capacity reactance of *the condenser for the alternation-fresecondary, the

. denser for the alternation-frequency of the supply current, and a across the condenser.

Si' ed by me at Boston, Massachusetts this gurteenth day of August 1909.

4MELVILLE EASTHAM;v

Witnesses:

` CHARLES D. WOODBERRY, JosErHINE H. RYAN.

spark-gap 1n shunt 

